Cyclic nucleotide metabolism is being studied in lymphocytes from patients with chronic lymphocytic leukemia and other disorders characterized by aberrant lymphocyte function. Cyclic AMP levels and adenyl cyclase activity are being assayed, and the response to prostaglandin E1 and beta-adrenergic stimulators is being assessed. The experiments are aimed at further exploring the possible role of cyclic AMP as a mediator of cell growth and differentiation, by examining its activity in "experiments of nature" in which these cellular functions are abnormal. BIBLIOGRAPHIC REFERENCES: Mendelsohn, J., M.M. Multer and J.L. Bernheim. Inhibition of human lymphocyte stimulation by steroid hormones: cytokinetic mechanisms. Clin. Exp. Immunol. 27:127-134, 1977. Bernheim, J.L. and J. Mendelsohn. Kinetics of DNA synthesis and cell proliferation in lymphocyte activation. Workshop review. In Proceedings of Eleventh Leukocyte Culture Conference, ed. D.O. Lucas, Academic Press, 1977 in press.